1. Technical Field
The present invention relates to a method of forming a stacked wiring, a manufacturing method of a liquid ejecting head, a wiring mounting structure, a liquid ejecting head, and a liquid ejecting apparatus, and particularly relates to a method of forming a stacked wiring and a wiring mounting structure, a manufacturing method of the ink jet recording head, an ink jet recording head, and an ink jet recording apparatus which are used for an ink jet recording head ejecting ink as the liquid.
2. Related Art
As a liquid ejecting head which ejects liquid droplets, an ink jet recording head ejecting ink as an example of the liquid is known. The ink jet recording head is provided with a flow path forming substrate (a second substrate) on which a pressure generating chamber communicating with a nozzle opening is formed, a piezoelectric actuator provided on one surface of the flow path forming substrate, and a protective substrate (a first substrate) which is bonded to the piezoelectric actuator of the flow path forming substrate, and ejects the ink from the nozzle opening by causing the piezoelectric actuator to generate a pressure change in the liquid inside the pressure generating chamber.
In such an ink jet recording head, a driver IC (a semiconductor device) is provided on the surface opposite to the surface which is bonded to the flow path forming substrate of the protective substrate, a through hole is formed in the protective substrate, and a lead electrode (a first wiring) which is connected to the piezoelectric actuator is caused to be exposed to the through hole. The through hole is inclined with respect to a formation surface of the lead electrode. Then, by passing through a side wall in which the through hole is inclined, a wiring terminal of the driver IC and the lead electrode of the piezoelectric actuator are electrically connected to each other via an inclined wiring (a second wiring) (for example, refer to JP-A-2006-289943).
The lead electrode and the inclined wiring are, for example, formed as follows. First, an adhesion layer is provided on the flow path forming substrate and the lead electrode which is formed from metal such as gold is formed on the adhesion layer. Then, the lead electrode is covered with a protective layer which is formed from the same material as that of the adhesion layer. Next, the inclined wiring is formed on the protective layer on the lead electrode through a wet etching method.
However, there is a concern in that the adhesion layer is side-etched by an etchant when the inclined wiring is formed through the wet etching method. In this manner, when the adhesion layer is etched, there is a concern in that the lead electrode peels off from the flow path forming substrate, thereby resulting in a conduction failure between the lead electrode and the inclined wiring. In addition, there is a concern that the piezoelectric actuator corresponds to a portion in which a conduction failure occurs does not work even as the liquid ejecting head, thereby resulting in a poor ink ejection.
Meanwhile, such problems exist not only in a manufacturing method of the ink jet recording head but also in a manufacturing method of the liquid ejecting head, and exist in a method of forming a stacked wiring which is used for the liquid ejecting head and other devices as well. In addition, such problems exist not only in the ink jet recording head but also in the liquid ejecting head and the liquid ejecting apparatus which includes the liquid ejecting head, and exist in a wiring mounting structure which is used for the liquid ejecting head and other devices as well.